1. Field of the Invention
This invention relates generally to a system for locating a target that has been struck by a projectile, and more particularly, to a device that is carried by an arrow, is detachable from the arrow upon contacting a target, and is attachable to the target. The system can include a combination of integral and detachable transponders. A standard hunting arrow fitted with a transponder that attaches to a game animal upon impact is provided. A system and method for detecting the transponder and thereby locating the game animal is also presented.
2. Background Information
Hunting game animals with a bow and arrow has a long tradition in many parts of the world. When an arrow is shot from a bow, it can often be difficult to determine whether it hits its target or not. If the arrow misses the target, it often disappears in the brush. The loss of arrows is a matter of one expense that the hunter would ideally like to avoid. Further, if the shot is successful and the arrow hits and fatally wounds a target animal, the animal sometimes travels a significant distance before it succumbs. Depending on the terrain and the weather conditions, it can often be difficult to quickly locate an animal that has been dispatched with an arrow. Under all circumstances, it would be desirable to locate a targeted game animal that has been struck by an arrow and to do so in an expeditious and efficient manner.
While the arrow sometimes remains embedded in the game animal, in many other instances (especially with relatively small game such as white-tail deer) the arrow passes completely through the animal. Therefore, a tracking system that solely relies upon a device that is integral to the arrow and that remains with the arrow would be of little use in this instance.
Various approaches to aid in locating wayward arrows or game animals that retain the arrows after impact, are represented in the prior art. For example, U.S. Pat. No. 5,468,000 provides an arrow with an integral attachment that can be activated to emit an audible signal to facilitate location of the arrow and/or animal.
Many of the “integral arrow” devices presented in the prior art are directed to altering the structure, and consequently the aerodynamic properties, of the arrow wherein, for example, the shaft of the arrow contains a radio transmitter that allows later location of the arrow.
When a radio transmitter is incorporated as part of the structure of the arrow itself, it is not only important that the arrow contact the animal, it is also essential that the arrow remain with the animal until the animal succumbs. Often, after being struck by an arrow, an animal can break off a part of the arrow (e.g., disabling the device) or dislodge the arrow entirely, thus limiting the utility of a locator device that is incorporated into the arrow itself. In addition, if the arrow passes entirely through the animal, an integral arrow tracking device will only allow location of the arrow and not the animal. An additional disadvantage of a transmitter that is built into a shaft of an arrow is the expense of designing and building customized arrows. It would therefore be desirable if a tracking device were provided that is adaptable for use with standard arrows and therefore does not entail the expense of designing and building customized arrows.
Some other approaches are directed to the attachment of radio transmitter to a “standard arrow” of a type that a majority of archery hunters would commonly own. For example, U.S. Pat. No. 5,450,614 provides a jacket-like radio receiver that slips over the shaft of a standard arrow. Another approach has been to insert a radio transmitter between the arrowhead (e.g., broadhead) and the shaft of the arrow, such as is shown in U.S. Pat. No. 4,885,800. Alternatively, a transmitter may be secured along the length of the shaft as is shown in U.S. Pat. No 5,167,417. All of these prior art solutions suffer from the same limitations described above, namely that the arrow may pass completely through the game animal taking the transmitter with it, or an arrow that remains embedded in the animal may become broken off and disable the device, thus failing to aid in the location of the animal. These devices may also cause an undesirable change in the aerodynamic properties of the arrow.
Still another approach allows for a detachable radio transmitter to be attached to the shaft of the arrow. Upon the arrow penetrating the animal, the electronic signaling device is detached from the arrow and is embedded into the hide of the wounded game animal. However, location of the transmitter along the shaft could affect the trajectory of the arrow. Affixing a detachable tracking device at the front of a conventional arrow, for example, as part of the broadhead itself, or as a releasable insert between the broadhead and shaft, could eliminate most if not all of the above described limitations and difficulties.
Radio transmitters have been the device of choice in this field. A radio transmitter actively generates a signal that can typically be received by a hand-held location device (i.e., a receiver) carried by the hunter. However, the use of a radio transmitter presents several problems.
A radio transmitter requires a energy source, such as a battery, to generate the radio signals. Batteries add both weight and expense to the device. Also, because battery life is limited, some type of switch is typically employed to activate the radio transmitter so that the battery does not run down prior to being utilized.
One approach to conserve battery life has been to use an inertia switch to activate the radio transmitter upon shooting the arrow. One distinct disadvantage of using such a switched transmitter is the added weight of the battery and switch. To maintain accuracy over conventional distances, the hunter must somehow compensate for the heavier projectile.
Another problem with using a battery powered transmitter relates to the finite life of the battery. If the transmitter is turned on too soon (e.g. prior to contacting the animal) or if the animal is not located soon enough after contact (e.g. before the battery expires) there is no way to locate the transmitter once the battery power has drained and a signal is no longer being generated.
Thus, while the above-presented body of art describes arrows with detachable radio transmitters, these references do not teach or suggest a conventional arrow having a detachable radio transponder located at the front of the arrow wherein upon impact the transponder is attachable to the target. Such an invention would improve the state of the art significantly.